[Nikwho]

I don't know if it is the most universally accepted method, but I used phosphoric acid on my car. I was using it at first to remove some surface rust. If you leave it on it creates a layer that prohibits rusting. I ended up misting it over the rest of my car that is sitting in bare metal over the winter. My wife pulls in and out of the garage in her car and all of the snow drips off as it melts. So my garage has lots of moisture in it over the winter. Not a touch of surface rust has formed on it! It is used and sold as concrete etcher at home depot. Its with the paint thinner in the paint section. It sells for only about $15/gallon. Works great. Its cheap, too! I think its called "Phosphoretch", Home Depot sells it in an opaque container with a yellow label.